Histidine orientation in artificial peroxidase regioisomers as determined by paramagnetic NMR shifts

Fe-Mimochrome VI*a is a synthetic peroxidase and peroxygenase, featuring two different peptides that are covalently-linked to deuteroheme. To perform a systematic structure/function correlation, we purposely shortened the distance between the distal peptide and the heme, allowing for the separation and characterization of two regioisomers. They differ in both His axial-ligand orientation, as determined by paramagnetic NMR shifts, and activity. These findings highlight that synthetic metalloenzymes may provide an efficient tool for disentangling the role of axial ligand orientation over peroxidase activity.

Automated summary

Fe-Mimochrome VI*a is a synthetic peroxidase and peroxygenase with two different peptides covalently linked to deuteroheme. Shortening the distance between the distal peptide and heme allowed for the separation and characterization of two regioisomers, which differ in activity and axial-ligand orientation. These findings suggest that synthetic metalloenzymes could be useful for understanding the role of axial ligand orientation in peroxidase activity.